Ruud Janssen studied Physics and Mathematics. He became active with mail art in 1980 and did several international mail art projects. From 1994 till 2001 he has conducted interviews with Fluxus and mail artists in different communication forms; the results have been published in booklets and on the internet since 1996. In later years he focused more on acrylic painting and individual correspondences.
Janssen publishes articles, magazines and booklets with his TAM-Publications and participates in international mail art projects, collaborations and exhibitions. He founded IUOMA (International Union of Mail-Artists) in 1988 and is also the curator of the TAM-Rubberstamp Archive, the result of a Mail Art collection that has been accumulated by him from 1983 till now. The archive contains prints, original rubberstamps, magazines and literature. It is the longest time a mail art project has run ever (details see link to latest online catalogue). In 1994 he started with his Mail-interviews which have been published as booklets and online. The interviews have a new concept where the question is sent in a specific communicationform and the interviewed person chooses his own way to get the answer back. This way the factor time is involved in each specific interview. Samples of interviewed persons are: Ray Johnson, Dick Higgins, Ken Friedman, Anna Banana, Mark Bloch, Patricia Tavenner, Michael Leigh, Alison Knowles and Guy Bleus.
In 2003 Litsa Spathi founded together with Ruud Janssen the Fluxus Heidelberg Center for which they are building up a collection of Fluxus material and where they also publish their own works.
Janssen was selected to publish an essay as one of eleven contemporary "New Fluxus" artists who are seen to 'inhabit the site of Fluxus, developing and interpreting the Fluxus tradition in a new way.' in a special double issue of the journal Visible Language on Fluxus. The double issue was developed by Owen Smith and Ken Friedman and published through the Rhode Island School of Design The other artists included as representing New Fluxus artists: Alan Bowman, Bibiana Padilla Maltos, David-Baptiste Chirot, David Cologiovani, Eryk Salvaggio, Cecil Touchon, mIEKAL aND, MTAA, Litsa Spathi, Sol Nte, and Walter Cianciusi.